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Disperse fine equiaxed α‐Al2O3 nanoparticles with a mean particle size of 9 nm and a narrow size distribution of 2–27 nm were synthesized using α‐Fe2O3 as seeds and isolation via homogeneous precipitation‐calcination‐selective corrosion processing. The presence of α‐Fe2O3 acting as seeds and isolation phase can reduce the formation temperature to 700°C and prevent agglomeration and growth of α‐Al2O3 nanoparticles, resulting in disperse fine equiaxed α‐Al2O3 nanoparticles. These α‐Al2O3 nanoparticles were pressed into green compacts at 500 MPa and sintered first by normal sintering to study their sintering behavior and finally by two‐step sintering (heated to 1175°C without hold and decreased to 1025°C with a 20 h hold in air) to obtain nanocrystalline α‐Al2O3 ceramics. The two‐step sintered bodies are nanocrystalline α‐Al2O3 with an average grain size of 55 nm and a relative density of 99.6%. The almost fully dense nanocrystalline α‐Al2O3 ceramic with finest grains achieved so far by pressureless sintering reveals that these α‐Al2O3 nanoparticles have an excellent sintering activity.

Hierarchical nanostructures consisting of TiO2 nanowire arrays and ZnO nanosheets were prepared and investigated as active materials in photoelectrochemical UV sensors.

Nanocrystalline microstructure is regarded as a strategic approach to overcome the brittleness of alumina ceramics, and the preparation of disperse equiaxed α‐Al2O3 nanoparticles is an essential step for the preparation of nanocrystalline alumina ceramics. In this work, disperse equiaxed α‐Al2O3 nanoparticles were prepared using α‐Fe2O3 as seed and isolation phase. At first, the composite of α‐Al2O3 nanoparticles embedded in α‐Fe2O3 matrix was obtained by calcining the precursor powder containing γ‐AlOOH and Fe(OH)3 (Fe3+/Al3+ mole ratio of 5) at 770°C for 2 h. Then disperse equiaxed α‐Al2O3 nanoparticles with a mean size of 12 nm and a size distribution from 2 to 40 nm without vermicular microstructure were obtained by removal of α‐Fe2O3 and other impurities in the composite through acid corrosion.